IDO1 and cancer: Clinical trials have shown effective antitumor activity and the restoration or activation of cancer immune surveillance functions with IDO inhibitors such as epacadostat (INCB024360), navoximod (GDC‐0919, NLG‐919), PF‐06840003, BGB‐5777, and linrodostat (BMS‐986205) in oncological models [175].